TOUCH QUIZ BUZZER

This circuit  gives the principle and operation similar to touch sensor .this circuit divide into three parts as 

• input
• 555 timer ic (monostable configuration )
• output (buzzer or light )

here in circuit diagram input  is  given at  touch plate or switch  and  output can obtain at buzzer or  light etc as your   require.

here  555  timer  ic  pin diagram  is  given(8 pin dip package)

  

DESCRIPTION:- 

 here  555 timer can operate  in monostable state  and  generated frequency is depend on resistor and  capacitor .in circuit reset pin  is connected to Vcc and control voltage connected to ground through  the capacitor .input is given to touch plate or switch  to input of bc547(npn) transistor output of transistor  connected to Vcc and emitter connected to ground   this is  very sensitivity compare to circuit without transistor . output taken at  pin 3 this is indicate using led  in software stimulation .given below.here  i m given  small pulse  to base of transistor .

WAVE FORM IN MONOSTABLE STATE 555 TIMER